Thermal transfer printers are widely prevalent which print characters or images on an object, such as an image-receiving sheet, by using an ink ribbon (thermal transfer sheet). The ink ribbon includes a ribbon (support layer) extending in a strip shape, and an ink layer containing a dye, etc. and formed on the ribbon. The ink ribbon is mounted and wound on a bobbin.
The bobbin, on which the ink ribbon is wound, generally includes a bobbin body and a driving flange mounted on the bobbin body as a separate member from the bobbin body. However, the provision of such a driving flange, as a separate member, in a bobbin body increases the number of constituent components and increases the production cost and, in addition, involves a cumbersome operation when disposing of the bobbin.
It is conceivable to form driving irregularities in the outer surface of a bobbin body. However, when winding a ribbon on the bobbin, a rubber touch roll pressing on the ribbon may come into contact with the driving irregularities, resulting in the formation of scratches on the touch roll.